I’ve always been told that the HD25SP is an inferior variant of the HD25-1 and so I never really bothered checking it out. Then, a few weeks ago two of my friends bought the HD25SP and said good things about it. The interesting thing is that they also own the HD25-1 and while the HD25SP is not quite as good as the HD25-1, both of them agreed that the HD25SP is a very good headphone in itself, and a much better value for the money (the HD25-1 sells for ~$300 outside of the US).
I finally got a loaner unit from my buddy Sem, and so I’ve been listening to it for a while now. The first thing I noticed is that although the build quality is identical, I didn’t quite like the slimmer headband of the SP model. For some reason it doesn’t hold the headphone in my head as well as the split headband of the HD25-1. The headband of the SP also clamps less, and the result is a looser fit which also lets more noise in and out. Now some people may appreciate the looser fit, but for me I’d take the firmer grip of the HD25-1.
When it comes to sound impressions, I must say that although the SP model is a notch down from the HD25-1, indeed it is still quite a good headphone in its own. It’s like comparing the Grado SR125i to the SR325is: nobody ever said that the SR125i is a bad headphone, just not quite as good art he SR325is. Most noticeable is the darker sound signature which at first may come out as sounding less detailed than the HD25-1. Yes, if I really go hard with the A-B comparison, the HD25-1 still reproduces a tiny better low level detail, but in reality the biggest difference certainly comes from the treble levels, where the HD25sP is more relaxed on the treble and instruments. If you happen to buy an HD25SP and feels like it can use more treble, the first thing that I’d recommend is to get the HD25 velour pads as it’ll give more treble as well as helping the phone to sound more open (the same effects can also be found on the HD25-1).
Another difference that I found between the two is that the HD25SP has less attack than the HD25-1. Still quite a forward headphone, but not as decisive as the HD25-1. And though bass body is fuller, the HD25-1 feels more impactful and tighter. It’s not quite a night and day difference, but it’s enough to make a difference in the energy in the music. The HD25-1 clearly rocks better, but the HD25SP is far from a laid back Hifi headphone too. In fact, the darker nature of the HD25SP makes it a better headphone for treble happy recordings.
Although the nominal impedance ratings are lower on the HD25SP, in reality it needs to be driven louder from the amplifier. The lower efficiency number at 114dB at 1kHz, 1Vrms is probably the cause here. The more limited frequency response range is not that bothersome for mainstream and casual music listening, and is only evident on critical listening sessions.
If I were moving A-B between the two headphones, it’s very evident that the HD25-1 is still the better model. Most evident is the more precise timbre and the minimal amount of reverb I get with the HD25-1. However, the HD25SP in itself clearly makes for a good $130 headphone, and for a lot of people it should be a better value for the money than the $300 HD25-1 model.